Effects of trade and poaching pressure on extinction risk for cacti in the Atacama Desert.

In this era of a global biodiversity crisis, vascular plants are facing unprecedented extinction rates. We conducted an assessment of the extinction risk of 32 species and 7 subspecies of Copiapoa, a genus endemic to Chile's fog-dependent coastal Atacama Desert. We applied the International Union for Conservation of Nature Red List Categories and Criteria enhanced by expert insights and knowledge. Our primary aim was to analyze the impact of trade and poaching on their extinction risk. We employed machine learning models, including multinomial logistic regression (MLR), decision tree (DT), and random forest (RF), to analyze the relationships between conservation status and various factors. These factors encompassed trade and poaching activities, landscape condition, human footprint, monthly cloud frequency, and biological traits such as evolutionary distinctiveness and maximum diameter. Seven taxa had an area of occupancy (AOO) of <10 km2, 10 additional taxa had an AOO of <20 km2, and 16 taxa had an AOO of ≤100 km2. This reassessment exposed a critical level of extinction risk for the genus; 92% of the taxa were classified as threatened, 41% as critically endangered, 41% as endangered, and 10% as vulnerable. MLR, DT, and RF exhibited accuracies of 0.784, 0.730, and 0.598, respectively, and identified trade and poaching pressure and landscape condition as the primary drivers of extinction risk. Our assessment of Copiapoa showed trade, poaching, habitat degradation, and their synergic impacts as the main drivers of the genus' extinction risk. Our results highlight the urgent need for nations to develop and enforce strategies to monitor and control trade and poaching pressure because these factors are crucial for the long-term persistence of desert plants.

Retos para la regulación del uso comercial de serpientes elápidas marinas en el Indo­Pacífico Resumen En estos tiempos de la crisis mundial de la biodiversidad, las plantas vasculares enfrentan una tasa de extinción sin precedentes. Evaluamos el riesgo de extinción de 32 especies y siete subespecies de Copiapoa, un género endémico al Desierto de Atacama. Aplicamos los Criterios y Categorías de la Lista Roja de la Unión Internacional para la Conservación de la Naturaleza mejoradas con información y conocimiento de expertos. Nuestro principal objetivo era analizar el impacto del mercado y la colecta ilegal sobre el riesgo de extinción de estas plantas. Usamos modelos de aprendizaje automático, incluyendo la regresión logística multinominal, los árboles de decisión y los bosques aleatorios, para analizar las relaciones entre el estado de conservación y diversos factores. Estos factores englobaron las actividades de mercado y colecta ilegal, condiciones del terreno, huella humana, frecuencia mensual de nubes y características biológicas como la singularidad evolutiva y el diámetro máximo. Siete taxones tuvieron un área de ocupación (ADO) <10 km2, diez taxones más tuvieron ADO <20 km2 y 16 taxones tuvieron ADO ≤100 km2. Este análisis expuso el nivel crítico del riesgo de extinción del género Copiapoa: el 92% de los taxones están clasificados como amenazados, 41% como en peligro crítico, 41% como en peligro y 10% como vulnerable. La regresión logística multinominal, los árboles de decisión y los bosques aleatorios exhibieron una certeza del 0.784, 0.730 y 0.598, respectivamente. También identificaron a la presión del mercado y la colecta ilegal y las condiciones del terreno como los principales factores detrás de riesgo de extinción. Nuestro análisis del género Copiapoa mostró que el mercado, la colecta ilegal, la degradación del hábitat y sus impactos sinérgicos como los principales factores detrás del riesgo de extinción del género. Nuestros resultados resaltan la necesidad urgente de que las naciones desarrollen y apliquen estrategias para monitorear y controlar la presión del mercado y la colecta ilegal pues estos son factores cruciales para la persistencia a largo plazo de las plantas de los desiertos.

The impact of Pleistocene glaciations and environmental gradients on the genetic structure of Embothrium coccineum.

The South American temperate forests were subjected to drastic topographic and climatic changes during the Pliocene-Pleistocene as a consequence of the Andean orogeny and glacial cycles. Such changes are common drivers of genetic structure and adaptation. Embothrium coccineum (Proteaceae) is an emblematic tree of the South American temperate forest (around 20°S of latitude) that has strongly been affected by topographic and climatic events. Previous studies have shown a marked genetic structure in this species, and distinct ecotypes have been described. Yet, little is known about their adaptive genetic responses. The main goal of this study was to investigate the effects of historical and contemporary landscape features affecting the genetic diversity and connectivity of E. coccineum throughout its current natural distribution. Using over 2000 single nucleotide polymorphisms (SNPs), we identified two genetic groups (a Northern and a Central-Southern group) that diverged around 2.8 million years ago. The level of genetic structure was higher among populations within the Northern genetic group than within the Central-Southern group. We propose that these differences in genetic structure may be due to differences in the assemblages of pollinators and in the evolutionary histories of the two genetic groups. Moreover, the data displayed a strong pattern of isolation by the environment in E. coccineum, suggesting that selection could have led to adaptive divergence among localities. We propose that in the Chilean temperate forest, the patterns of genetic variation in E. coccineum reflect both a Quaternary phylogenetic imprint and signatures of selection as a consequence of a strong environmental gradient.